PTFE Failure rate?
MK2s Noob here. Just spent 12 hours building mine (many breaks - and I will not proceed until I understand exactly what I am doing). Led to a perfect perpendicular report after calibration. 
I came from a CTC Bizer (Makerbot dual clone). Whenever I had filament tangles which led to a jam, or a filament runout, I wound up with heat creep that would melt the PTFE liner causing it to fail and cause the jam. I replaced the PTFE tubes quite a few times. As difficult as the MK2 was to build I am not looking forward to tear downs due to clogs. So, I made a filament run out sensor to use with octopi. It works, but unfortunately it only pauses the print but keeps the heat on. This worries me. If the printer is left for a few hours in pause mode with the heat full on, will heat creep cause me all kinds of problems like I experienced in the past.
Also, does any know of a way to make the filament run out plugin in Octopi cancel the print rather than simply pause it? Or, is there a setting in the MK2 that will force the heat to turn off during a pause? If filament runs out or tangles and jams, I would rather fail the print and start over rather then try and resume it.
Thanks for any insight! I already love this printer!!! 😎
Re: PTFE Failure rate?
George
The PTFE tube is quite safe, as long as the extruder fan is running.
Unlike many nozzles (such as the Lite6 and a lot of clones), the V6 has the PTFE located well away from the heat.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: PTFE Failure rate?
so if you are using the pi to interrupt the print why not go the extra mile and add in a fet to interrupt the power to the hotend heater?
the ptfe should be safe up at the temperatures you are running at, as has been said keep the fan running.
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Re: PTFE Failure rate?
PJR and Phil thanks for the replies.
Okay, so I am not concerned about the PTFE tube based on your responses. Lets say a print pauses and it is hours before I return home to cool it down. Will there be any issues with molten filament sitting in the hot end without being extruded for hours?
As for the FET idea, sounds great, but I am only a hobbyist. If someone else has done it and provides a guide, I am confident enough to follow it. I surface mount added a FET to my CTC for a filament cooling fan, but i had a guide that told me what to buy, and how to install it. Engineering one, writing code, and all that... way above my learned abilities. Thanks for the idea though!